Display device and manufacturing method thereof

1. A display device, comprising: a first substrate and a second substrate; a plurality of first signal lines and a plurality of second signal lines located on the first substrate; a first insulation layer located between the first signal lines and the second signal lines, wherein a plurality of cavities are located in the first insulation layer, and the first insulation layer has a plurality of thin films located on the cavities; a plurality of active components electrically connected to the first signal lines and the second signal lines; a display medium layer located between the first substrate and the second substrate; and a plurality of ultrasonic transducers located between the first substrate and the second substrate, wherein each of the ultrasonic transducers comprises: a first electrode, wherein the first electrode and one of the first signal lines belong to a same layer and are electrically connected with each other; and a second electrode, wherein the second electrode and one of the second signal lines belong to a same layer and are electrically connected with each other, and one of the cavities and one of the thin films are sandwiched between the first electrode and the second electrode.

2. The display device of claim 1 , wherein a range of the cavities is defined by the first insulation layer and the first electrodes.

3. The display device of claim 1 , further comprising: a black matrix formed on the second substrate and overlapped with the ultrasonic transducers.

4. The display device of claim 1 , further comprising: a plurality of spacers located between the first substrate and the second substrate and overlapped with the cavities.

5. The display device of claim 1 , further comprising: a plurality of isolation materials located between the first substrate and the second substrate, wherein the first insulation layer further comprises a plurality of openings, the openings are connected to the cavities, and the isolation materials are filled in the openings.

6. The display device of claim 1 , further comprising: a passivation layer located on the second signal lines, the second electrodes, and the first insulation layer, wherein the first insulation layer further comprises a plurality of openings, the openings are connected to the cavities, a portion of the passivation layer is filled in the openings, and the passivation layer has a plurality of grooves corresponding to the openings.

7. The display device of claim 6 , further comprising: a plurality of isolation materials located between the first substrate and the second substrate, and the isolation materials are filled in the grooves.

8. The display device of claim 1 , wherein the ultrasonic transducers are suitable for fingerprint recognition.

9. The display device of claim 1 , wherein the display medium layer comprises a liquid crystal or an organic light-emitting material.

10. A manufacturing method of a display device, comprising: providing a first substrate; forming a first conductive layer on the first substrate, wherein the first conductive layer comprises a plurality of first signal lines and a plurality of first electrodes connected to the first signal lines; forming a plurality of sacrificial material layers on the first electrodes; forming a first insulation material layer to cover the first signal lines, the first electrodes, and the sacrificial material layers; forming a second conductive layer on the first insulation material layer, wherein the second conductive layer comprises a plurality of second signal lines and a plurality of second electrodes connected to the second signal lines; patterning the first insulation material layer to form a first insulation layer comprising a plurality of openings, wherein the openings expose the sacrificial material layers, and the first insulation layer has a plurality of thin films located on the sacrificial material layers; removing the sacrificial material layers to form a plurality of cavities in the first insulation layer, wherein the cavities and the thin films are sandwiched between the first electrodes and the second electrodes; forming a passivation layer on the second conductive layer and the first insulation layer; forming a display medium layer on the passivation layer; and covering a second substrate on the display medium.

11. The manufacturing method of the display device of claim 10 , further comprising: forming a plurality of isolation materials in the openings.

12. The manufacturing method of the display device of claim 10 , wherein a portion of the passivation layer is filled in the openings, and the passivation layer has a plurality of grooves corresponding to the openings.

13. The manufacturing method of the display device of claim 12 , further comprising: forming a plurality of isolation materials in the grooves.

14. The manufacturing method of the display device of claim 10 , wherein the first conductive layer further comprises a plurality of gates electrically connected to the first signal lines, and the manufacturing method of the display device further comprises forming a plurality of channel layers overlapped with the gates, wherein the second conductive layer further comprises a plurality of sources and a plurality of drains electrically connected to the channel layers, and the sources are electrically connected to the second signal lines.